You could always up your nic level if it's not doing it for you. Maybe you started too low
I figure, no point in burning through 6 ml in a day vaping constantly at 12mg/ml when you could do 2ml in a day at 18ml for example. Or you could just wait to get used to the lower nic level as suggested above.
Either way, nothing to be concerned about unless you start feeling sick, nauseous or shaky - then you know you've vaped too much nic and it's time to put it down for an hour or so until you're feeling better.
Congrats on quitting!